militarywikiaorg-20200222-history
BL 4 inch naval gun Mk I – VI
|wars= |designer= |design_date= |manufacturer= |production_date= |number= |variants= |weight= |length= |part_length=Mk I 22.5cwt : bore (25 calibres)DiGiulian Mk II - VI : bore (27 calibres) 120 inches total |width= |height= |crew= |cartridge= |caliber= |action= |rate= |velocity=Mk I 13cwt : Mk I 13cwt gun : 1180 ft/sec firing 25 pound projectile with 3lb 4oz RLG2 (gunpowder). Text Book of Gunnery 1887, Table XVI page 313 Mk II - VI : Mk II - VI 1,900 ft/s with projectile, using S.P. (gunpowder) or cordite MK I size 5 propellant (Text Book of Gunnery, 1902) |range= |max_range=Mk II-VI Text Book of Gunnery, 1902 |sights= |breech=3-motion screw |recoil= |carriage= |elevation= |traverse= }} The 'BL 4-inch gun Mk I - Mk VI'Mk I - Mk VI = Marks 1 through to Mark 6. Britain used Roman numerals to denote Marks (models) of ordnance until after World War 2. This article covers the first six models of British BL 4-inch naval guns were a family of early British breech-loading 4-inch naval guns. History 13 cwt Mk I, 15 calibres This was the first 4-inch BL gun. With its short (60-inch total) barrel it had a range of only 5,500 yards.DiGiulian 22.5 cwt Mk I, 25 calibres With its longer barrel (100 inch bore) Mk I had a range of 7,200 yards. Both early Mk I types were quickly withdrawn from service following the explosion of a similar BL 6 inch Mk II gun on board HMS Cordelia in June 1891. Mk I 22.5 cwt continued to be used for training. 26 cwt Mks II - VI, 27 calibres The improved 27-calibres Mk II gun and subsequent Marks, often referred to as 4 inch 26 cwt, replaced the early Mk I versions in service. The longer barrel (108 inch bore : 27 calibres) gave it a range of 7,700 yards.Text Book of Gunnery 1902 Mk II guns and later Marks armed the following warships : * as re-gunned in 1885 * as re-gunned in 1885 *''Pygmy'' class composite screw gunboats of 1888 * s launched in 1889 * as re-gunned in 1891 * s of 1894 The gun was succeeded in its class from 1895 by the QF 4 inch gun Mk I. QFC 4 inch gun A small number of these guns were converted to QF to use the same cartridges as the QF 4 in gun. They were designated Mk I/IV, I/VI etc. depending on which Mark of BL 4-inch had been converted. All had a bore of 27.85 calibres after conversion, with a muzzle velocity of 2,177 ft/second. Surviving examples * A gun from 1888 at Explosion! The Museum of Naval Firepower, Gosport from Victorian Forts and Artillery website * A gun from HMS Gannet, mounted on top of Calshot Castle at the entrance to Southampton Water from Victorian Forts and Artillery website See also *List of naval guns Notes and references Bibliography * Text Book of Gunnery, 1887. LONDON : PRINTED FOR HIS MAJESTY'S STATIONERY OFFICE, BY HARRISON AND SONS, ST. MARTIN'S LANE * Text Book of Gunnery, 1902. LONDON : PRINTED FOR HIS MAJESTY'S STATIONERY OFFICE, BY HARRISON AND SONS, ST. MARTIN'S LANE * Tony DiGiulian, British Early 4" (10.2 cm) Breech Loaders External links *Mk V or VI gun as movable fortification gun, on siege overbank carriage. At Victorian Forts and Artillery website *Mk I diagram and photos at Victorian Forts and Artillery website Category:Naval guns of the United Kingdom Category:100 mm artillery Category:Victorian-era weapons of the United Kingdom